1 files changed, 8 insertions, 11 deletions
diff --git a/absl/base/internal/spinlock_wait.cc b/absl/base/internal/spinlock_wait.cc
index 3f8e43f0..60a85196 100644
--- a/absl/base/internal/spinlock_wait.cc
+++ b/absl/base/internal/spinlock_wait.cc
@@ -4,7 +4,7 @@
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//      https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ -32,7 +32,7 @@
 #endif
 
 namespace absl {
-inline namespace lts_2018_12_18 {
+inline namespace lts_2019_08_08 {
 namespace base_internal {
 
 // See spinlock_wait.h for spec.
@@ -66,19 +66,16 @@ int SpinLockSuggestedDelayNS(int loop) {
   r = 0x5deece66dLL * r + 0xb;   // numbers from nrand48()
   delay_rand.store(r, std::memory_order_relaxed);
 
-  r <<= 16;   // 48-bit random number now in top 48-bits.
   if (loop < 0 || loop > 32) {   // limit loop to 0..32
     loop = 32;
   }
-  // loop>>3 cannot exceed 4 because loop cannot exceed 32.
-  // Select top 20..24 bits of lower 48 bits,
-  // giving approximately 0ms to 16ms.
-  // Mean is exponential in loop for first 32 iterations, then 8ms.
-  // The futex path multiplies this by 16, since we expect explicit wakeups
-  // almost always on that path.
-  return static_cast<int>(r >> (44 - (loop >> 3)));
+  const int kMinDelay = 128 << 10;  // 128us
+  // Double delay every 8 iterations, up to 16x (2ms).
+  int delay = kMinDelay << (loop / 8);
+  // Randomize in delay..2*delay range, for resulting 128us..4ms range.
+  return delay | ((delay - 1) & static_cast<int>(r));
 }
 
 }  // namespace base_internal
-}  // inline namespace lts_2018_12_18
+}  // inline namespace lts_2019_08_08
 }  // namespace absl